Objectives Discuss the current evidence for opioids in labor - - PowerPoint PPT Presentation

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Pain Management Options in Laboring Patients

Jennifer Lucero, MD Assistant Professor Clinical Anesthesia UCSF Dept. of Anesthesia

Objectives

• Discuss the current evidence for opioids

in labor

• Review the Role of Nitrous Oxide in labor
• Discuss Non-Pharmacologic strategies
• Review the Role of Epidural Analgesia in

labor

OPIOIDS IN LABOR

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Fentanyl Pharmacokinetics

• Short acting synthetic μ-1 & μ-2 opioid

receptor agonist

• Rapid onset of action in 30-60 sec
• Peak analgesic effect within 2.5 min
• Cumulative effect with repeated or prolonged

administration

• Increased context sensitive half-life: ≈70 min
• Elimination in neonates varies: 75-440 min

Remifentanil Pharmacokinetics:

Ultra-Short Acting (mu-1 opioid receptor agonist)

• Rapid onset (onset = 30-60 sec; Peak = 2.5 min)
• Inactive metabolites (plasma esterases)
• Short Context-Sensitive half-life (3.5 min)
• “

“ “ “Respiratory Depression” ” ” ” half-life (2.5 min)

Hinova et al. Systemic Remifentanil for Labor Analgesia. Anesthesia & Analgesia. 2009; 109(6): 1925-9. Babenco et al. The pharmacodynamic effect of a remifentanil bolus on ventilatory control. Anesthesiology 2000; 92:393-8.

Remifentanil and Pregnancy

• The placenta contains nonspecific esterases
• Fetal esterases nearly fully developed at birth
• Within 5-10 minutes of turning off an infusion

there is virtually no residual effect.

• Remifentanil can be turned off minutes before

delivery without fetal respiratory depression

Maternal-Fetal Transfer

Kan, R, et al.. Anesthesiology; 1998;88:1467-74

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Maternal-Fetal Transfer

Kan, R, et al.. Anesthesiology; 1998;88:1467-74 Douma et al. Br J Anesth 2010; 104(2): 209-15.

*

Douma et al. Br J Anesth 2010; 104(2): 209-15.

Meperidine Fentanyl Remifentanil Satisfaction 7.0 7.3 8.1* Epidural 34% 15%* 13%* Supp O2 8% 2% 12% Sat < 95% 33% 56%* 74%* Apgar 1 8.6 8.5 8.9 Apgar 5 9.7 9.6 9.9

* = p<.05 vs. Demerol

RCT Remifentanil vs. Epidural

Volmanen et al. Acta Anesthesiol Scand 2008; 52: 249-55.

N=45 Total

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• Remifentanil Group: transient maternal

desaturation observed more frequently

• Fentanyl Group: larger number of neonates

required resuscitation

• Pain scores were no different between the

groups

NITROUS IN LABOR

Nitrous oxide

Patients: 11% Complete 61% Considerable 28% Slight or None Midwives: 7% Excellent 35% Good 49% Adequate 9% inadequate

Rosen 1969 BMJ, Vol3:263

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• 58 publications reviewed

– 2 studies good quality – 11 studies fair – 46 studies poor

• Nitrous less effective pain relief than epidural
• Heterogeneous outcomes for satisfaction
• No difference in neonatal outcomes
• More good quality studies needed

Coping Algorithm vs. Pain Scores in Labor

• Developed to provide an alternative pain

scores

• Formalized assessment tool for laboring

women

• Future Research

– Validation with different cultures ethnicities – Validation from patient perspective – Generalizability at other institutions

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NON-PHARMACOLOGIC METHODS

Listening to Mothers- 2006

• Survey of women who gave birth in a hospital

in 2005

• 1,573 survey participants
• Ages 18-45
• Only single gestations (multiple gestations

excluded)

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EPIDURAL ANALGESIA

Thorp, JA et al .The effect of continuous epidural analgesia on cesarean section for dystocia in nulliparous women. Am J Obstet Gynecol. 1989; 161(3): 670-5 Thorp, JA et al.Epidural analgesia and cesarean section for dystocia : risk factors in nulliparas. Am J perinatology1991;8 (6):402-410 Thorp, JA et al. The effect of Intrapartum Epidural Analgesia on Nulliparous Labor: Randomized, Controlled, Prospective Trial. Am J Obstet Gynecol 1993 196(4):851-858.

Historically, a Bad Reputation

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Oxytocin Augmentation 26.7% 58.3% Head Malposition 4.4% 18.8% Assisted Vaginal Delivery 11.1% 18.8% Cesarean Delivery 2.2% 25.0% Thorp, JA et al. The effect of Intrapartum Epidural Analgesia on Nulliparous Labor: Randomized, Controlled, Prospective Trial. Am J Obstet Gynecol 1993 196(4):851-858.

…when feasible, obstetric practitioners should delay the administration of epidural analgesia in nulliparous women until cervical dilatation reaches 4–5 cm and other forms of analgesia be used until that time.

Outcome Neuraxial Systemic P Value

Cesarean 17.8 % 20.7% .31 Instrumental 19.6% 16.0% .13 Oxytocin 92.3% 94.5% .38 Neuraxial Duration 440 min 330 min .001 APGAR <7 (1min) 16.7% 24.0% .01 APGAR <7 (5min) 1.4% 2.5% .28

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E DIT O R S ’ C HO IC E

E arly versus late initiation of epidural analgesia in labor: Does it increase the risk of cesarean section? A randomized trial American Journal of Obstetrics and Gynecology (2006) 194, 600–5

In the absence of a medical contraindication, maternal request is a sufficient medical indication for pain relief during labor…ACOG recognizes that many techniques are available for analgesia in laboring patients. None of the techniques appears to be associated with an increased risk of cesarean delivery.

No increased risk of Cesarean Delivery or Instrumented Vaginal Delivery with early epidural placement

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Routine Epidural analgesia may be inferior to Epidural on Request leading to more Operative Deliveries: Vaginal and Cesarean Delivery

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It’s Complicated

Labor dysfunction causes increased pain resulting in maternal request for epidural? Maybe OR Epidural causes increased second stage and operative vaginal delivery? Not Likely Complex interplay of Labor, Labor management, and epidural analgesia Labor epidural currently the most effective in reducing pain scores and producing most effective analgesia in labor

Conclusions

• Opioids are safe for both mother and neonate
• Remifentanil & Fentanyl PCA are alternative
• ptions for women who epidural is

contraindicated

• Nitrous Oxide has a role in labor analgesia

Conclusions

• Pain scores should not be the only assessment
• f Labor analgesia
• There is a role of non-pharmacologic options

in labor

• Epidurals do not increase your risk of
• perative deliveries
• Epidural analgesia is best at maternal request

and not as routine analgesia

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